Conventionally, two types of devices, namely thermionic electron-emitting devices and cold cathode electron-emitting devices, are known as electron-emitting devices. The cold cathode electron-emitting devices include field emission type electron-emitting devices, metal/insulator/metal type electron-emitting devices, and surface-conduction type electron-emitting devices.
The surface-conduction type electron-emitting device utilizes the phenomenon that electrons are emitted by flowing a current through a small-area thin film formed on a substrate, in parallel with the film surface. The present applicants have made many proposals for surface-conduction type electron-emitting devices having novel arrangements and their applications. The basic arrangement, manufacturing method, and the like are disclosed in, e.g., Japanese Patent Laid-Open Nos. 7-235255 and 8-171849.
The surface-conduction type electron-emitting device is characterized by comprising on a substrate a pair of facing device electrodes, and a conductive film which is connected to the pair of device electrodes and partially has an electron-emitting portion. Part of the conductive film is fissured.
A deposition film mainly containing at least either carbon or a carbon compound is formed at the end of the fissure.
A plurality of electron-emitting devices can be arranged on a substrate, and wired to fabricate an electron source having a plurality of surface-conduction type electron-emitting devices.
The display panel of an image forming apparatus can be formed by combining this electron source and fluorescent substances.
The panel of the electron source is conventionally manufactured as follows.
As the first manufacturing method, an electron source substrate is fabricated on which a plurality of devices, each made up of a conductive film and a pair of device electrodes connected to the conductive film, and wiring lines connecting the plurality of devices are formed. The fabricated electron source substrate is set in a vacuum chamber. After the interior of the vacuum chamber is evacuated, a voltage is applied to each device via external terminals to form a fissure in the conductive film of each device. Gas containing an organic substance is introduced into the vacuum chamber. A voltage is applied again to each device via external terminals in the atmosphere in which the organic substance exists, thereby depositing carbon or a carbon compound near the fissure.
As the second manufacturing method, an electron source substrate is fabricated on which a plurality of devices, each made up of a conductive film and a pair of device electrodes connected to the conductive film, and wiring lines connecting the plurality of devices are formed on the substrate. The fabricated electron source substrate and a substrate having fluorescent substances are joined via a support frame to fabricate the panel of an image forming apparatus. The interior of the panel is evacuated via the exhaust pipe of the panel, and a voltage is applied to each device via external terminals of the panel to form a fissure in the conductive film of each device. Gas containing an organic substance is introduced into the panel via the exhaust pipe. A voltage is applied again to each device via external terminals in the atmosphere in which the organic substance exists, thereby depositing carbon or a carbon compound near the fissure.
These manufacturing methods have been adopted. However, the first manufacturing method requires a larger vacuum chamber and an exhaust device coping with a high vacuum as the size of the electron source substrate increases. The second manufacturing method requires a long time for evacuation from the inner space of the panel of the image forming apparatus and introduction of gas containing an organic substrate into the inner space of the panel.